Plot: gbrainy is a free and open brain teaser game for GNOME designed for use in education. It is licensed under the GNU GPL. The game was written in C# and has since been ported to the Sugar graphical environment, to Microsoft Windows. Wikipedia
Plot: GLtron is a 3D snake game based on the light cycle portion of the film Tron. The game is free and open-source software and has been ported to many mobile and non-mobile operating systems such as Windows, MacOS, Symbian and Android over the years. Wikipedia
Plot: GridWars or GridWars 2 is a video game inspired by Bizarre Creations' Geometry Wars by Canadian developer Marco Incitti. The first version of the game was released as freeware on December 21, 2005 on Marco Incitti's Blitz Creations website. Wikipedia
Plot: Liquid War is an open source multi-player action game based on particle flow mechanic. Thomas Colcombet developed the core concept and the original shortest path algorithm, the software was programmed by Christian Mauduit. Liquid War 6 is a GNU package distributed as free software and part of the GNU...
Plot: XPilot is a multiplayer video game. It is open source and runs on many platforms. Although its 2D graphics have improved over time, they still resemble the style of Thrust. Gameplay includes Capture the Flag, base defense, racing and deathmatches. Wikipedia
Plot: Kanagram is an educational game that creates anagrams, re-assortment of letters in a word, and the user needs to guess what the original word is. It is licensed under the GNU Public License v2, and it is part of the kdeedu package, and the user interface is designed to be approachable even by very...